part of part of M cell of gut Should double check and see if M cells are particular to a specific region. ZFA:0009293 https://cellxgene.cziscience.com/cellguide/CL_0000682 An absorptive cell of the gut epithelium that endocytoses microorganisms and intact macromolecules from the gut lumen and transports them to the subepithelial space where they are presented to antigen-presenting cells and lymphocytes. FMA:62929 BTO:0003600 M cell M cells, or microfold cells, of the gut are specialized epithelial cells found in the lining of the gut, specifically in the follicle-associated epithelium of mucosa-associated lymphoid tissue, where they function as sentries against toxins and pathogens. M cells are characterized by apical microfolds (hence their alternate name) which express unique adhesion molecules that enable them to sample the luminal macromolecules. Other morphological features that distinguish M cells from other intestinal mucosal cells include sparse microvilli and a reduced thickness of the glycocalyx, which permits adhesion while not hindering the transport of molecules. They also have unique intraepithelial invaginations on the basolateral side which are filled with macrophages and other immune cells that can process the engulfed macromolecules quickly. These morphological characteristics enable M cells to serve a dual role in immune responses. They initiate the immune response by transporting antigens (such as toxic or pathogenic substances) across the epithelial layer to lymphocytes and antigen-presenting cells in the underlying lymphoid tissue. This specialized transport process is called 'transcytosis.' They also have specialized molecules like glycoprotein-2 for bacterial uptake. Simultaneously, M cells help maintain immune tolerance to food antigens and commensal bacteria, preventing unnecessary reactions to non-pathogenic substances and hypersensitivity conditions. While these functions are crucial for well-being, M cell dysfunction can lead to serious conditions like Crohn's disease and other inflammatory bowel diseases. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) microfold cell M-cell intestinal epithelial cell Homo sapiens Peyer's patch epithelium